The evolutionary success of angiosperms depends largely on the unique feature of producing fruits, which protect and nourish the seeds, and at maturity facilitate efficient seed dispersal. Therefore, fruits are considered as an important innovative trait in the adaptive radiation evolution process of angiosperms. Characterizing the genes responsible for fruit shape determination and revealing the evolutionary relationships of these genes to the adaptation of fruits is a central topic in evolutionary developmental biology (Evo-Devo). In this study, we used C. rubella (Cr22.5), which belongs to Brassicaceae and develops a unique heart-shaped fruit, as the model system. Through a forward genetic screen of an ethyl methanesulfonate (EMS)-induced mutant population. One mutant, heartless (htl), was isolated due to its strong defects in the outgrowth of the fruit shoulders. By constructing the back cross populations (BC4F2) of htl with WT and using bulked segregant analysis (BSA) we cloned the putative genes underlying the htl mutant, which encodes a dehydrogenase-like protein. In addition, compared with wild type, the htl mutant exhibits defects throughout both vegetative and reproductive development, such as changes in leaf and fruit shape, and a decrease in seed quantity. This demonstrates that the CrHTL gene regulates multiple developmental processes. Currently, we are conducting research on the function and evolution of CrHTL in order to uncover its biological role in fruit morphogenesis.